The measurement of leak rate by differential pressure loss is a standard leak test technique. However, the present invention not only measures leak rate by differential pressure loss but also compensates for the temperature of the test part and provides a system for "fine-tuning" the temperature correction.
Further in accordance with the invention, and as will become more apparent from the specific embodiment about to be described, the chamber of a test part is filled with gas under pressure and the pressure drop over a predetermined test period is measured. Because it has been discovered that temperature has an affect on pressure drop, the measured pressure drop is corrected to compensate for the temperature of the test part. The amount of the compensation is derived from a table of estimated correction values. These correction values are adjusted and fine-tuned during the course of the testing of a run of test parts.
The object of this invention is to provide a method of and apparatus for leak testing having the foregoing features. Other objects, features and advantages of the invention will become more apparent as the following description proceeds, especially when considered with the accompanying drawings.